Free Electron Lasers Theory Challenges G Dattoli Syncchrotron

Free Electron Lasers : Theory Challenges? G. Dattoli

Syncchrotron Radiation …an old Story

Synchrotron Radiation an old story started before Laser( also on human scale) Radiation emitted by charged particles moving in magnets

What is a Free Electron Laser? A Tool to transform the kinetic energy of an electron beam into electromagnetic radiation with Laser like properties

What are the basic elements of a FEL? A) An accelerator Capable of providing an e-beam with «suitable» characteristics B) An undulator C) An Optical Cavity if the device is operated as an Oscillator

What is the Role of the accelerator An RF Accelerating system brings to a relativistic Energy E an electron Beam of current I The power associated to the e-beam is PUMP POWER ?

Energy and frequency Letardi -Chart

The New Livingston Plot R. Assmann B. Hidding

new scheme: PDPWFA simulation electric field electron density accelerated bunch Te. V p-bunches are available from conventional accelerators PDPWA accelerates e- in the wake of such p bunches to Te. V energy over a few 100 m electric fields = 100 x ILC or CLIC e- energy vs distance e- energy spread vs distance Allen Caldwell, K. Lotov, A. Pukhov, F. Simon, Nat. Phys. 5 (2009) 363.

new scheme: PDPWFA simulation electric field electron density accelerated bunch Te. V p-bunches are available from conventional accelerators PDPWA accelerates e- in the wake of such p bunches to Te. V energy over a few 100 m electric fields = 100 x ILC or CLIC e- energy vs distance e- energy spread vs distance Allen Caldwell, K. Lotov, A. Pukhov, F. Simon, Nat. Phys. 5 (2009) 363.

The Challenges A) Reduce the costs B) reduce the sizes C) Improve the «light» coherence properties D) Increase the number of experimental stations

Towards «Bonsai» FEL

An exercise: X-Band LINAC (70 Me. V/m)

ELEMENTS FOR A STRATEGY A) Reduce the undulator length using exotic devices (Laser Wave undulators, R. F. Undulators, …. ) B) Reduce the size of the accelerator using different

Plasma accelerating schemes

Plasma accelerating scheme

Is the future coming?

The dream

LIGHT AND PARTICLES in the 21 st century

Spare Transparencies

Frascati How many «free electron devices» ? For a ny kind of emission mechanism (Cerenkov, Smith Purcell…) a FEL device can be conceived

Interest For Plasma Fusion Applications Resonance condition electron cyclotron frequency in plasma Parallel component of the refractive index Resonance frequency 250 GHz Power 3 MW Efficiency >30%

Required Parameters

An Exercise to fix Numbers Operating Frequency 250 GHz Beam current 5 A Beam voltage 700 k. V Longitudinal velocity spread 0. 3 – 0. 5 % Energy spread 1 – 2 % Cavity magnetic field 5 T